Lithium ion battery has been widely used for cellular phones, notebook personal computers and camcorders.
Development and technology trend of lithium ion battery are reviewed. The origin of lithium ion battery was the research on secondary battery using an electroconductive polymer, polyacetylene, as the negative electrode. Then the focus was shifted from polyacetylene to carbonaceous materials which also have π electrons. They were combined with a lithium ion-containing metal oxide, LiCoO2 as the positive electrode.
Capacity of the lithium ion battery has been increased every year and present capacity is twice as much as the initial value.
This improvement of capacity has been achieved by improvement of carbonaceous materials.
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